竖直U型地热换热器流体出口温度的计算模型

以圆柱热源理论为基础,引入“近热史”和“远热史”的概念,采用简化的方法建立了变热流情况下换热器与周围土壤的传热计算模型,利用该模型在已知远地点温度Tg的情况下可求解出钻孔壁温度Tw。随后引入形状因素的概念,建立了管内稳定传热的计算模型,结合前述求得的Tw,得出了计算换热器内循环流体的出口温度Tout的方法。

Modeling of the Out-flowing Temperature of a Vertical U-tube Ground Heat Exchanger

In this paper, the concept of recent heat history and far heat history are introduced basing on the classic cylindrical heat source solution. A computing model was built for the heat transfer between the heat exchanger and ground under varying heat rate with a simple method. Given the far field temperature Tg, the bore boundary temperature Tw can be achieved. Then the concept of shape factor was introduced to build the model for the steady heat transfer inside the bore. Finally, by combining the two models, a method to compute the out-flowing temperature of a vertical U-tube ground heat exchanger was achieved.